JP4333343B2 - Hot metal desiliconization sludge casting method and hot metal desiliconization method using the same - Google Patents

Description

  The present invention relates to a tilting iron used when pre-treating hot metal discharged from a blast furnace casting floor before subjecting it to converter refining and the like, and a desiliconization method using the same. The present invention relates to a tilting rod used in, and a desiliconization method using the same.

  The hot metal taken out from the blast furnace usually contains 0.2 to 0.8% by mass of silicon. If this hot metal is fed directly to the steelmaking process, which is the next process, and silicon is removed by oxidation, the removal efficiency of phosphorus and carbon that are simultaneously oxidized is lowered. Therefore, in recent years, it has become widespread to remove silicon by adding a desiliconizing agent to hot metal in a blast furnace casting floor.

  In many cases, the desiliconization treatment in the blast furnace casting floor is performed by using an iron oxide-based desiliconizing agent in the flowing hot metal in hot metal flowing into the topped car or hot metal ladle, which is a receiving (conveying) container. Is added to oxidize silicon contained in the molten iron and shift it to slag. This method is called a cast bed desiliconization method in particular, as distinguished from the desiliconization performed in the steelmaking process.

  In recent years, the level of impurities in steel products has become stricter, and refining to a lower level than before has been directed. In the case of silicon, in order to efficiently remove phosphorus in the next steelmaking process, it is required to reduce the concentration to 0.1% by mass or less in the blast furnace casting floor. In response to this requirement, an operation is also directed so that the silicon in the hot metal discharged from the blast furnace is stably 0.3 mass% or less.

  However, when removing such a low level of silicon, the proportion of iron oxide consumed in the oxidation reaction of silicon is even lower. As a result, it is necessary to further improve the reaction efficiency in casting bed desiliconization.

The casting floor desiliconization method can be broadly divided into
(1) A method of applying a desiliconizing agent in hot metal,
(2) A method of applying a desiliconizing agent in an inclined casting rod,
(3) A method of spraying the desiliconizing agent on the tilting rod,
(4) There is a method of injecting a desiliconizing agent in a deep bottom desiliconization tank provided in the hot metal. Of these, the injection method (4) has a large wear on the injection lance and it is difficult to maintain and maintain the hot metal. Therefore, the topping method (1), (2) or the top spraying method (3) Mainly adopted.

  By the methods (1) to (3) described above, the silicon removal agent and the silicon in the hot metal do not react 100%, and a portion of the silicon removal agent remains unreacted and slags. This slag-ized desiliconizing agent flows into the transfer container through the inclined pouring outlet portion. The slag that naturally falls together with the hot metal is stirred in the container by the potential energy of the falling flow, and the desiliconization reaction further proceeds.

  In other words, the desiliconization reaction occurs in the cast iron desiliconization process in the hot metal, the tilting iron and the transfer container. The main ones are decanting rods and transport containers. The reaction in the transfer container depends on stirring by natural falling. Therefore, it is stirring and mixing in the vicinity of the so-called waterfall in the falling flow, and its control is difficult. In other words, it can be said that the key to the improvement of the reactivity in the casting bed desiliconization is how to improve the reactivity of the tilting iron.

  In order to improve the efficiency of the reaction under the same supply amount and supply speed of the desiliconizing agent, the contact area between the desiliconizing agent and the hot metal may be increased. For this purpose, it is necessary to disperse the desiliconizing agent and increase the mixing with the molten iron. However, as described above, the desiliconizing agent introduced by hot metal or decanting iron becomes slag and aggregates before reaching the decanting iron outlet. In order to increase the contact area between the agglomerated slag desiliconizing agent and the hot metal, a strong stirring force is required.

  In order to give this stirring force, methods such as mechanical stirring and gas stirring are typical, but these methods are difficult to put into practical use in terms of durability in a high-temperature flow system such as a tilting rod. Then, the following technique using the potential energy of the blast furnace cast floor is disclosed.

  In Patent Document 1, a receiving guide with a cylindrical outlet is provided at the outlet of the tilting iron to allow the hot metal to flow vertically, and a hot metal pool is formed in the receiving guide to allow the hot metal to fall naturally from the cylindrical outlet. Therefore, a technique for improving the stirring and mixing by generating a vortex is disclosed.

  Patent Document 2 uses a container capable of generating a swirling flow using the falling energy of hot metal when the hot metal flows out, and includes an iron oxide-containing desiliconizing agent in the swirling hot metal to improve the reaction efficiency. The technique to make it disclose is disclosed.

  These technologies use the falling energy of hot metal to generate vortex (swirl flow) and mix hot metal and desiliconizing agent, and the effect can be obtained only with the container shape without external operation. . However, in the former, the hot metal flows down vertically from the receiving guide, and in the latter, the hot metal is discharged below the swirl flow generating container and poured into the receiving (conveying) containers. .

  That is, when such an operation is performed, the receiving guide and the swirl flow generating container are positioned immediately above the receiving (conveying) container, and cover the upper part. As a result, it becomes difficult not only to monitor the inside of the receiving (conveying) container, but also a device for measuring from the upper part of the container such as a weight type level meter or a microwave level meter cannot be used. In the case of a transport container having a relatively small container opening such as a topped car, the influence is particularly great.

Furthermore, in the latter, it is shown in the Examples that a dedicated container is used as an aspect of the invention, but when a dedicated container is introduced, it is unavoidably necessary to introduce auxiliary equipment for supporting the container, It is disadvantageous in terms of equipment cost and maintenance management.
Japanese Unexamined Patent Publication No. 3-153810 Japanese Patent Laid-Open No. 2001-40410

  According to the present invention, an improved tilting rod eliminates the need for an independent container or ancillary equipment, and further, a tilting rod capable of obtaining a high desiliconization reaction efficiency without any problem in receiving operation of a transport container, and a degassing using the same. An object is to provide a method for treating silicon.

  In order to solve the above-mentioned problems, the present inventors have made extensive studies focusing on the improvement of the tilted rod shape, and have realized the results in the present invention.

That is, the present invention is a tilting iron used for desiliconization of hot metal in a blast furnace casting floor, comprising a hot metal outlet at a hot metal outlet, and connected directly below the outlet of the hot metal and hot metal to connect the hot metal in a horizontal direction. Alternatively , it is an inclined injection rod characterized in that it is provided with a rod that is fed obliquely downward and led to the transport container.

  In this invention, the tilting iron is composed of a receiving chamber for receiving hot metal and a wax shaped portion connected to the outlet thereof, a streamline of the hot metal flow flowing from the receiving chamber into the wax shaped portion, It is preferable to decenter the wax and the axis of the outlet of the shaped part.

  Moreover, you may equip the both ends of the said tilting rod with the said wax-shaped part.

In addition, the present invention, when performing desiliconization of hot metal in a blast furnace casting floor,
(a) It consists of a receiving chamber for receiving hot metal and a funnel-shaped part connected to the outlet,
(b) The streamline of the hot metal flow flowing from the receiving chamber into the wax-shaped part and the axis of the wax and the outlet of the shape part are eccentric,
(c) Use an inclined pouring rod that is connected directly below the outlet of the funnel-shaped part and feeds the molten iron horizontally or obliquely downward to guide it to the transport container. The ratio of the hot metal volume flow rate (m ³ / min) passing through the wax-shaped part is in the range of 0.5 to 3.0.

  According to the present invention, by improving the tilting rod, it is possible to obtain a high desiliconization reaction efficiency without the need for an independent container or ancillary equipment and without any trouble in the receiving operation of the transfer container.

  Hereinafter, embodiments of the present invention will be described in detail.

  In the present invention, only a part of the tilting rod 4 is improved so that it can be easily applied to the existing equipment of the blast furnace casting floor as shown in FIG. That is, as shown in FIG. 2, the shape part 8 is provided in the tilting rod. This eliminates the need to introduce dedicated incidental equipment as in the case of introducing a dedicated container. In addition, FIG. 3 shows a cross-sectional view taken along the line AA in FIG.

  At the same time, it is important to provide a rod 10 that guides the molten iron 11 to the transport container (for example, the topped car 5) just below the wax 9 of the tilting rod 4 and the outlet 9 of the shape portion. The hot metal 11 flowing out from the outlet 9 of the wax-shaped portion has vortex inertia and flows out in the circumferential direction of the outlet. Therefore, some kind of guide is necessary. However, if the guide guides the hot metal 11 vertically below as in the prior art described above, it is difficult to manage the receiving.

In the present invention, a rod 10 is provided that is connected directly below the outlet 9 of the wax-shaped part and feeds the molten iron 11 horizontally or obliquely downward. As a result, the receiving guide and the swirl flow generating container of the tilting rod 4 are not positioned immediately above the transport container, so that conventional receiving management is possible. It is desirable that the ridge 10 is directed in a range of 45 ° downward from the vertical with respect to the vertical axis of the wax-shaped portion 8.

  In addition, the tilting iron 4 includes a receiving chamber 7 for receiving the hot metal 11 and a funnel-shaped portion 8, a streamline of the hot metal flow flowing from the receiving chamber 7 into the funnel-shaped portion 8, and an outlet 9 of the funnel-shaped portion. It is preferable to decenter the axis. Normally, the tilting iron 4 accepts the hot metal 11 falling from the hot metal 2, but if the falling hot metal 11 is introduced into the shape part 8 as it is, the flow in the circumferential direction in the wax shape part 8 becomes weak, and the vortex flow is reduced. It is disadvantageous to formation. If hot metal is once received in the hot metal chamber 7 and then the hot metal 11 is guided substantially horizontally along the circumferential direction of the shaped portion 8, a vortex can be obtained very effectively. For that purpose, it is important to decenter the streamline of the hot metal flow flowing from the receiving chamber 7 into the wax shaped part 8 and the axis of the outlet 9 of the wax shaped part.

  Furthermore, a funnel shaped portion 8 may be provided at both ends of the tilting rod 4. By providing at both ends, not only continuous processing is possible, but also the symmetry of the tilting rod 4 is obtained, and there is no difficulty in the equipment.

The ratio Q / D of the hot metal volume flow rate Q (m ³ / min) passing through the wax shape portion to the outlet diameter D (m) of the wax shape portion using the tilting iron 4 provided in the present invention is in the range of 0.5 to 3.0. If the desiliconization treatment of the hot metal 11 is performed under such conditions, extremely high desiliconization reaction efficiency can be enjoyed. If the above ratio Q / D is less than 0.5, the hot metal flow will flow out without forming a vortex in the shaped part 8 even if it is wax, and effective stirring and mixing will not be achieved. If the ratio Q / D is larger than 3.0, the hot metal 11 fills the wax-shaped part 8 and an effective vortex for stirring and mixing cannot be obtained.

  In the present invention, the desiliconization treatment in the blast furnace cast floor has been disclosed, but the present invention can naturally be applied to other facilities for producing a silicon-containing hot metal by a smelting reduction method or the like.

[Example 1]
In the blast furnace 1 (the amount of 9000 tons / day) shown schematically in FIG. 1, the sinter dust as an iron oxide-based desiliconizing agent is transferred to the hot metal flow falling from the hot metal 2 to the tilting iron 4. 6 was projected from above through a silicon removal treatment. The desiliconizer basic unit was 20 kg / ton.

A plan view and a cross-sectional view of the tilting rod 4 used are shown in FIGS. The ratio of the hot metal volume flow rate of 1 m ³ / min to the exit diameter of the wax-shaped portion of 0.5 m was 2. Thus, the desiliconization treatment of the hot metal 11 was performed, and the relationship between the concentration of molten iron before desiliconization treatment and the desiliconization oxygen efficiency was investigated. This is an invention example. The silicon removal oxygen efficiency is calculated by the following formula.

Desiliconization oxygen efficiency (%) = 100 x O _M / O _F
O _M : Oxygen amount associated with Si desiliconized from hot metal (kg)
O _F : Oxygen content in desiliconizer (kg)
On the other hand, as a comparative example, the desiliconization treatment was performed in the same manner as in the invention example except that the tilted iron 4 not provided with the wax-shaped portion 8 was used, and the relationship between the outgoing Si concentration before the desiliconization treatment and the desiliconization oxygen efficiency. investigated.

  FIG. 4 is a graph showing the relationship between the output Si concentration and the desiliconization oxygen efficiency. As is apparent from FIG. 4, it is clear that the desiliconization reaction efficiency is greatly increased by using the tilting rod 4 of the present invention.

[Example 2]
The desiliconization treatment was performed in the same manner as in Example 1 except that a tilted iron having a different outlet diameter was used in the blast furnace 1 (the amount of 9000 tons / day) shown in FIG. It was. The desiliconizer basic unit was 20 kg / ton. The ratio of the hot metal volume flow rate of 1 m ³ / min to the exit diameter of 1.0 m of the wax-shaped part was 1.0.

  In this way, desiliconization treatment was performed, and the relationship between the concentration of unloaded Si before desiliconization treatment and the desiliconization oxygen efficiency was investigated. This is an invention example.

  On the other hand, as a comparative example, except that a tilted iron without a wax-shaped part was used, the desiliconization treatment was performed in the same manner as the invention example, and the relationship between the outgoing Si concentration before the desiliconization treatment and the desiliconization oxygen efficiency was investigated. did.

  FIG. 5 is a graph showing the relationship between the outgoing Si concentration and the desiliconization oxygen efficiency. As is apparent from FIG. 5, it is clear that the desiliconization reaction efficiency is greatly increased by using the tilting rod of the present invention.

[Example 3]
The desiliconization treatment was performed in the same manner as in Example 1 except that tilt casting rods having different exit diameters were used in the blast furnaces (milling amount 2500 ton / day) of the blast furnace with different amounts of milling. The desiliconizer basic unit was 20 kg / ton. The ratio of the hot metal volume flow rate of 0.33 m ³ / min to the outlet diameter of 0.4 m of the wax-shaped part was 0.83.

  In this way, desiliconization treatment was performed, and the relationship between the concentration of unloaded Si before desiliconization treatment and the desiliconization oxygen efficiency was investigated. This is an invention example.

  On the other hand, as a comparative example, except that a tilted iron without a wax-shaped part was used, the desiliconization treatment was performed in the same manner as the invention example, and the relationship between the outgoing Si concentration before the desiliconization treatment and the desiliconization oxygen efficiency was investigated. did.

  FIG. 6 is a graph showing the relationship between the output Si concentration and the desiliconization oxygen efficiency. As is clear from FIG. 6, it is clear that the desiliconization reaction efficiency is greatly increased by using the tilting rod of the present invention.

[Example 4]
The desiliconization treatment was performed in the same manner as in Example 1 except that tilt casting rods having different exit diameters were used in the blast furnaces (milling amount 2500 ton / day) of the blast furnace with different amounts of milling. The desiliconizer basic unit was 20 kg / ton. The ratio of the hot metal volume flow rate of 0.33 m ³ / min to the outlet diameter of 0.16 m of the wax-shaped part was 2.1.

  In this way, desiliconization treatment was performed, and the relationship between the concentration of unloaded Si before desiliconization treatment and the desiliconization oxygen efficiency was investigated. This is an invention example.

  On the other hand, as a comparative example, except that a tilted iron without a wax-shaped part was used, the desiliconization treatment was performed in the same manner as the invention example, and the relationship between the outgoing Si concentration before the desiliconization treatment and the desiliconization oxygen efficiency was investigated. did.

  FIG. 7 is a graph showing the relationship between the output Si concentration and the desiliconization oxygen efficiency. As apparent from FIG. 7, it is clear that the desiliconization reaction efficiency is greatly increased by using the tilting rod of the present invention.

It is an arrangement figure showing typically an example of equipment arranged in a blast furnace cast floor. It is a top view which shows typically the example of the tilting rod of this invention. It is sectional drawing of the AA arrow in FIG. It is a graph which shows the relationship between a tapping Si density | concentration and desiliconization oxygen efficiency. It is a graph which shows the relationship between a tapping Si density | concentration and desiliconization oxygen efficiency. It is a graph which shows the relationship between a tapping Si density | concentration and desiliconization oxygen efficiency. It is a graph which shows the relationship between a tapping Si density | concentration and desiliconization oxygen efficiency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Hot metal 3 Skinma 4 Inclined iron 5 Topped car 6 Lance 7 Receiving chamber 8 Wax shape part 9 Wax shape part exit
10 樋
11 Hot metal

Claims (4)

A tilting iron used for desiliconization of hot metal in a blast furnace casting floor, with a hot metal outlet at the hot metal outlet and connected directly under the hot metal outlet to feed the hot metal horizontally or diagonally downward. A tilting rod characterized in that it is provided with a rod for feeding and guiding it to the transport container.   The inclined injection rod is composed of a receiving chamber for receiving hot metal and a wax-shaped portion connected to the outlet thereof, a streamline of the hot metal flow flowing from the receiving chamber into the wax-shaped portion, and an outlet of the wax-shaped portion. The tilting rod according to claim 1, wherein the axis is eccentric.   The inclined injection rod according to claim 2, wherein the wax-shaped portion is provided at both ends of the inclined injection rod. When performing desiliconization of hot metal on the blast furnace casting floor, it consists of a receiving chamber that receives the hot metal and a braze-shaped part connected to the outlet of the hot metal, and a streamline of the hot metal flow that flows from the receiving chamber into the brazed part Using an inclined injection rod with a rod that is eccentric to the axial center of the wax and the shape part, connected directly under the outlet of the wax shape part, and fed hot metal in the horizontal direction or obliquely downward to lead to the transfer container. A method for desiliconizing hot metal, wherein the ratio of the molten iron volume flow rate (m ³ / min) passing through the shape portion to the outlet diameter (m) of the shape portion is in the range of 0.5 to 3.0.

Images